1. Technical Field
The present invention relates to a developing device and an image forming device.
2. Related Art
Heretofore, a developing device has been known in which a circumferential speed of a photoreceptor is switchable between two or more levels of circumferential speed within a pre-specified range, and sleeves of a forward developing roller and a backward developing roller of a developing device are turned by respectively separate drive systems and variable speed motors. If the circumferential speed of the sleeve of the forward developing roller is represented by Va (m/s), the circumferential speed of the sleeve of the backward developing roller is represented by Vw (m/s) and the circumferential speed of the photoreceptor is represented by Vp (m/s), the circumferential speeds of the sleeves of the forward developing roller and the backward developing roller are respectively independently changed in accordance with switching of the circumferential speed of the photoreceptor such that Va, Vw and Vp satisfy a pre-specified relationship.